This article revisits the influential "Leviathan" hypothesis, which posits that tax competition limits the growth of government spending in decentralized countries. I use panel data to examine the effect of fiscal decentralization over time within countries, attempting to distinguish between decentralization that is funded by intergovernmental transfers and local taxation. First, I explore the logic whereby decentralization should restrict government spending if state and local governments have wide-ranging authority to set the tax base and rate, especially on mobile assets. In countries where this is most clearly the case, decentralization is associated with smaller government. Second, consistent with theoretical arguments drawn from welfare economics and positive political economy, I show that governments grow faster as they fund a greater portion of public expenditures through intergovernmental transfers.For good or ill, fiscal decentralization is commonly thought to restrict the growth of government spending. Just as tax competition in an era of globalization is believed to place constraints on the revenue-raising capacity of governments, interjurisdictional competition within decentralized countries is believed to hamper government's ability to tax. For those who see government as a revenue-hungry beast, this is a welcome muzzle. For others, fiscal decentralization creates a worrisome "race to the bottom" that favors capital over labor and prevents governments from providing important collective goods. Pushing the normative and ideological questions aside, this article seeks to determine whether there is a link between decentralization and smaller government. At first glance the proposition seems doubtful: throughout the era of globalization and fiscal decentralization in the latter part of the twentieth century, public sectors have grown faster than private sectors around the world. On average, government expenditures accountedThe author wishes to thank